Important Molecules - Unit 1 Flashcards
Carbon Compounds
- Forms covalent bond (two atoms sharing a pair of electrons)
- Can form up to 4 bonds
- Important in proteins, lipids, nucleic acids and carbs
4 Common Functional Groups
- Hydroxyl (alcohol)
- Amine (protein)
- Carboxyl (protein)
- Methyl (protein)
Metabolism
- The sum of all reactions in an organism
- Consists of ‘pathways’ where one molecule is turned into another
- Two parts: Anabolism and Catabolism
Anabolism
- Things coming together
- Large molecule forms from small molecules with energy (ATP)
- Condensation reactions
- Ex. Photosynthesis
Catabolism
- Things breaking apart
- Large molecule turns into a small molecule and releases energy
- Hydrolysis reactions
- Ex. Digestion
Water
- Polar (particle charges on each end, bent shape)
- Covalent bonds
- Attraction between h and o molecules are hydrogen bonds
Waters Unique Properties
- Cohesive - Sticks to itself, ex. water transport in xylem
- Adhesive - Sticks to other polar molecules, ex. adhesion to cellulose in plants
- Thermal Properties
1. High specific heat capacity - A large amount of energy is required to heat up, and release to cool
2. High latent heat of vaporization - Large amounts of energy required to break h bonds and evaporate - Solvent properties - dissolves substances, dissolved polar covalent and ionic compounds, molecules form shells that prevent them from sticking together.
Hydrophilic vs. Hydrophobic
Hydrophilic - Substances that dissolve and adhere to water (salt)
Hydrophobic - Substances that can’t dissolve or adhere to water (lipids)
Transport of Substances in Blood Plasma
NaCl, AA, Glucose - Dissolved in plasma
O2 - Carried by hemoglobin
Fats, Cholesterol - Carried in Lipoprotein complexes in plasma
Carbohydrates
- Made of C, H and O, often end in ‘ose’
- Immediate energy source and energy storage
- Builds other molecules
- Used in cell membrane recognition and structures of plant cells
Types of Carbohydrates
Monosaccharides - 1 sugar unit, 3-7 C atoms, sweet taste, several polar -OH groups, soluble in water, ring structure
Disaccharides - 2 monosaccharides linked by condensation reactions, double ring structure
Polysaccharides - many monosaccharides
Examples of Polysaccharides
Cellulose - Unbranched, B D-glucose, chain alternating up and down, have ‘Cellulose Microfibils’ cellulose bonding parallel in hydrogen bonds
Starch - A D-glucose, same directions, two types:
1. Amylose - Plants store glucose in insoluble form, helix form
2. Amylopectin - Branched, glucose can be loaded or unloaded quickly due to many points
Glycogen - Branched, stores glucose in insoluble form in liver and muscle cells
Lipids
- Non-polar, mostly hydrophobic hydrocarbons
- Don’t form polymers
- Types of lipids:
Triglycerides, steroids, phospholipids
Triglycerides
- Fats - Solid at room temp, liquid at body temp
- Oils - Liquid at both temps
- Used for nutrition, energy storage and insulation
- Formed by 3 FAs and glycerol through a condensation reaction.
Fatty Acids
- A long chain of C and H with a Carboxyl group, 4-24 C long
- Saturated - Each C has an H, single bonded, straight chains, solid at room temp, animal sources
- Unsaturated - Monounsaturated has 1 double bond, polyunsaturated has 2 or more double bonds, kinked chains, liquid at room temp, plant sources
Cis-unsaturated FA - Naturally occurring , H on same side of the double bond, kinked chain
Trans-unsaturated FA - Not naturally occurring, H on opposite side of double bond, straight chain, solid at room temp.
Proteins
- Made up of AA’s containing an amino group, carboxyl group, carbon and R group
- Polypeptides are chains of AA’s that form proteins linked by condensation reactions
- Oligopeptide: 2-20 AA
- Polypeptide: 20+ AA
Diversity of Amino Acids and Polypeptides
- Unique R groups
- 20 different AAs, 9 we have to consume
- Some can be modified to make more AAs
- Polypeptide is a chain of AAs linked by ribosomes, there are 20^n possible sequences, range from 20-10,000 AAs
- Instructions are stored in base sequences
Shapes of Proteins
- Shape determines function, 2 shapes:
1. Globular (carrying), hydrophilic outside, hydrophobic inside, water-soluble, enzymes or carriers
2. Fibrous (structure), elongated chain, water-insoluble, physically tough and stretchy
Proteomes
- All proteins produced by organisms
- Not fixed, varies over time
Examples of Proteins and Functions
Rubisco - Catalyst, produces C
Insulin - Reduces glucose concentration
Immunoglobin - Produces antibodies
Rhodopsin - Pigment that absorbs light, nerve impulses
Collagen - Structure of skin and blood vessels
Spider Silk - Resistant to breakage
Denaturation
- Permanent change to protein
- Heat, breaks bonds
- pH, breaks bonds or causes new ones to form, changing the structure
Active Sites and Enzymes
- Globular proteins that catalyze reactions
- 4000 different enzymes in a living cell
- Substrates are the substances converted into products by the enzymes
- Lock and Key: Enzyme and substrate are structurally the same and chemically attracted
- Induced Fit: Less rigid, enzyme changes shape a bit
Enzyme Activity
- Substrate binds to the active site by random collisions in the cytoplasm
- Substrate changes to products
- Products separate from the active site, the enzyme can bind again
Factors Affecting Enzyme Activity
- Temp - Energy increases and so does probability to collide, too much heat can cause denaturation
- pH - Enzymes have a specific range, and will denaturate when out of it
- Substrate Concentration - More substrates will increase the rate of reactions, it will plateau once all are filled
- Denaturation can result in a precipitate
Immobilized Enzymes
- Used in industry, attached to a material to limit movement or trapped in gels.
- This is done to increase concentration, to recycle, to separate easier, and to stabilize
Lactose-Free Milk
- Lactose is mixed with lactase to create galactose and glucose
- Increases sweetness, less crystallization in ice-cream, shortens production time for cheeses and yogurts
DNA and RNA
DNA: Large molecules (2m/cell), genetic info, doesn’t leave the nucleus, ATGC
RNA: genetic info, mRNA, tRNA, rRNA, AUGC
Structure of a nucleotide: 5-C sugar, phosphate group, N-base, condensation reactions and phosphodiester bonds
Difference Between DNA and RNA
- DNA has a deoxyribose sugar, and RNA has a ribose sugar
- DNA is double-stranded, RNA is single-stranded
- Have different bases
Structure of DNA
- Helix
- Anti-parallel nucleotides linked by H bonding
Replication of DNA
- DNA splits and becomes 2 templates
- Nucleotides added along templates
- 2 strands form, each with half new, half old DNA (semi-conservative)
Helicase
- Separate the strands by breaking H bonds, requires energy, doughnut shape.
DNA Polymerase
- Multiple polypeptide subunits, joins nucleotides to template, moves in 5’ to 3’ direction, catalyzes phosphodiester bonds and proof reads, mistake only occur 1/1B.
Transcription
-mRNA copies DNA, then moves to cytoplasm
Translation
- mRNA binds to small subunit of ribosome
- tRNA and matching anticodon binds to ribosome
- Codon binds to ribosome (max 2)
- Ribosome transfers AA forming a peptide bond
- First tRNA is released
- New tRNA moves in
- Ribosome transfer AA chain to the next AA forming a peptide bond
- 4,5 and 6 are repeated until STOP codon appears
Ribosomes
2 subunits:
- Small, binds to mRNA
- Large, binds to tRNA and catalyzes peptide bonds
Cell Respiration
Enzymes break Organic compounds into useable energy (ATP). ATP can’t be transferred; each must make their own.
3 Types of Activity Energy (ATP) is Required For.
- Synthesizing large molecules
- Active transport across membranes
- Moving things through the cell
ATP
Formed by linking a phosphate to an Adenosine and a diphosphate (ADP) with a high energy bond. Energy is easily released by splitting ATP. All processes release heat energy, raising body temp, but is soon lost in the environment; all cells require constant ATP.
Anaerobic Respiration
Breaks down glucose without oxygen. Only 2 ATP is produced. Used in 3 circumstances:
1. Oxygen runs out in cells
2. Short, rapid burst of ATP needed
3. Oxygen-deficient environments
In animals, glucose is broken down into lactate.
In yeasts and plants, glucose turns into ethanol and CO2.
Lactate and ethanol are toxic and must be removed.
Aerobic Respiration
Breaks down glucose using oxygen. Enzyme-controlled reactions, mostly in mitochondria. Up to 38 ATP produced. Glucose turns into CO2 and H2O(waste products, CO2 is excreted and H2O is used again).
Respirometers
Used to calculate the rate of respiration by measuring the consumption of oxygen. Uses 6O2 and creates 6CO2, V doesn’t change, CO2 is absorbed and V decreases. Movement in capillary tubes / minute measures rate of O2 consumption.
Photosynthesis and limiting factors
CO2 and water when met with sunlight energy turn into glucose and O2 (waste). Can be limited by temp, light intensity or CO2 concentration.
Wavelengths of light
Violet is the shortest, red is the longest. Low frequency has longer wavelengths, less energy, and vice-versa. UV, X and gamma rays are harmful.
Chlorophyll and photolysis
Chlorophyll absorbs all colours other than green. All oxygen in photosynthesis comes from photolysis, which releases electrons and oxygen.
Impacts of photosynthesis
- Creating a more stable atmosphere, 2% O to 21%.
- More O2 formed the ozone layer
- iron compounds in the oceans oxidized.
